The human ability to mentally activate or rehearse perceptual images such as particular sensations or experiences in the absence of the external perceptual stimulus which gives rise to the images. This is achieved, in part, by activating those regions of the brain responsible for processing the sorts of perceptions being simulated. For example, humans can mentally simulate a particular kind of redness, even in the absence of perceiving a red entity. Events can also be simulated, such as the stages involving in filling a car up with petrol, including mentally rehearsing the actions involved in taking the petrol cap off, removing the petrol nozzle from the pump, placing it in the petrol tank, pressing the lever so that the petrol flows into the tank and so on. The ability to simulate can be prompted for by language and is central to some recent theories in cognitive linguistics such as blending theory and Embodied construction grammar.